Various heat transfer recording methods have been known so far. Among these methods, dye diffusion transfer recording systems attract attention as a process that can produce a color hard copy having an image quality closest to that of silver halide photography. Moreover, this system has advantages over silver halide photography: it is a dry system, it enables direct visualization from digital data, it makes reproduction simple, and the like.
In the fields of the dye diffusion transfer recording system, various printers capable of printing at a higher speed than conventional printers have been recently developed and distributed in the markets. High speed printing is a performance required to shorten the time required for users who use self service printers to wait at the shop until printing is finished.
In recent years, good circumstances for users who print at the shop have been prepared and there are therefore many opportunities afforded for the installation of printers out of doors. The outdoor environment in summer is severer than indoor environments in the point of temperature and humidity. This gives rise to such a new problem that when a high-temperature printing in association with high-speed printing is made in a high humidity environment in summer, gloss unevenness involving many fine cells that are considered to be derived from steam in the atmosphere appear on a printed product. This problem, on the contrary, leads easy occurrence of lack of uniformity on the highlight part, in a severe environment of a low-temperature and low-humidity environment in winter.
In the meantime, it is known to use indoaniline type dyes as dyes (see JP-A-6-99676 (“JP-A” means unexamined published Japanese patent application)), and to use silicone oil in a heat-sensitive transfer layer (see JP-A-9-202058). It is also known to form a barrier layer between the support and the heat-sensitive transfer layer (see JP-B-7-102746 (“JP-B” means examined Japanese patent publication) and JP-A-2005-231354).
However, the heat-sensitive transfer sheets described in these documents are unnecessarily satisfactory to solve the above problems and it is therefore desired to provide a solution to these problems.